Tooth Mobility – Causes, Treatment

Introduction
Healthy gums and teeth are essential for the power of speech and beautiful smile.

“Mouth is the mouthpiece of mind”.

Mobile teeth are concerned not only for the patient, but also to the dentist, because it is the critical stage where the tooth lies between two “S” i.e. to be saved or sacrificed.

Tooth mobility is an important feature of periodontal disease. This is evidenced by the large number of devices and method of tooth mobility assessment that have been developed and tested. Tooth mobility has been considered and investigated as an indirect measure of the functional condition of the periodontium as well as possible aggravating co-factor for periodontal disease. Tooth mobility is considered to be of paramount significance of establishment of diagnosis, prognosis and treatment plan.

Definitions
The degree of looseness of tooth beyond physiologic movement.

TERMINOLOGIES
1. Physiologic / Normal Mobility
It refers to the limited tooth movement or tooth displacement that is allowed by the resilience of an intact and healthy periodontium when a moderate force is applied to the crown of the tooth examined. (Muhlemann 1951).

2. Pathologic tooth mobility
It is any degree of perceptible movement of a tooth faciolingually, mesiodistally or axially when a force is applied to the tooth. (M.J. Perlitsh 1980)

3. Altered tooth mobility
It is an alteration of the mobility characteristics of a tooth, which represents a transient or permanent change in periodontal tissues. (Giargia and Lindhe 1997). An increased TM may be associated with different physiologic or pathologic phenomena while decrease mobility usually is result of therapy.

4. Functional mobility
Functional mobility is the movement of teeth during function or parafunction.
5. Normal tooth mobility
It is more during early mornings and progressively decreases. Muhlemann (1960) reported that tooth mobility was 0.4 – 0.12 mm for 500 gm force applied. The incisors have the highest (0.1 – 0.12 mm) and molars the lowest (0.4 –0.8mm). Children and females exhibit higher values than adults and males respectively.

6. Increased / Static tooth mobility
It is a form of stabilized mobility. It is usually due to TFO, but may be due to periodontal diseases. But the periodontal structures have become adapted to an altered functional demand. It is self limiting and normal for that tooth with remaining bony support.

7. Increasing / Progressive tooth mobility
It is of progressive nature and can be identified only through a series of repeated tooth mobility measurements carried out over a period of several dogs or weeks.

8. Hypermobility
A form of increased mobility persisting after completion of periodontal treatment. It is often referred to as “residual mobility”. It has 2 phases, a developing phases and a permanent phase.

9. Reduced tooth mobility
As seen in ankylosed tooth after failing replantation or if autogenous bone grafts are placed in contact with detached root surface.

STAGES OF TOOTH MOBILITY
Tooth mobility occurs in 2 stages, namely
1) Initial / Intra socket stage (ITM)
2) Secondary stage (STM)

 Initial / Intra socket stage (ITM):
When a small force is applied to the crown of a tooth, the resistance of tooth supporting structures against displacement of root is low in the initial phase of force application and crown is moved by 0.5 mm to 0.1 mm which was called initial tooth mobility (ITM) by Muhlemann (1954) and is the result of intra alveolar displacement of root.

ITM depends on structure and organization of periodontal ligament. In the pressure zone there is a 10% reduction in the width of the periodontal ligament and in the tension zone there is a corresponding increase. The magnitude of the “Initial tooth mobility” varies from individual to individuals from tooth to tooth, and is mainly dependent on the structure and organization of PDL. The ITM value of ankylosed teeth is therefore zero.

Secondary stage (STM) :
When a large force (up to 500 pounds) is applied to the crown, the fiber bundles on the tension side can not offer sufficient resistance to further root displacements. The additional displacement of the crown that is observed in “Secondary tooth mobility” is allowed by distortion and compression of the periodontal ligament in the pressure side.

Aetiology
Local and systemic factors are implicated.
Local factors:
1. Bone loss or loss of tooth support:
2. Trauma from occlusion:
3. Hypofunction:
4. Extension of inflammation from the gingiva or from the periapex into the periodontal ligament
5. Periodontal surgery temporarily increases tooth mobility
6. Pathology of jaws like tumors, cysts, ostemylitis etc.
7. Tooth morphology (Crown and root shape)
Flat contacting surface – thin, narrow septa – less bone support.
Convex or bell shape – flat and wide septa more bone support increase in number, size of roots – more one support.
8. Overjet and over bite are directly proportional to tooth mobilit

9.The spread of inflammation from an acute periapical abscess may increase tooth mobility in the absence of periodontal disease.

Systemic factors:
1. Age: Mobility is positively related to age of the individual (Wasserman 1973) changes in the PDL that have been reported with aging include decreases numbers of fibroblasts with more irregular structure.
2. Sex and Race: Slightly higher incidence seen in females and Negroes. (Wasserman 1973).
3. Menstrual cycle: Burdine and Friedman (1970) observed increased horizontal tooth mobility during 4th week of menstrual cycle.
4. Oral contraceptives: Studies by knight and wade, Das, Bhowmick and Dutta indicate that periodontal disease and attachment loss were more common among women on pills. However Friedman (1972) found tooth mobility to be less among ovulatory drug users.
5. Pregnancy: Ratietschak (1967) has reported tooth mobility in pregnancy and has attributed it to physico-chemical changes in periodontium.
6. Systemic disease: Certain systemic diseases aggravate periodontal disease i.e. Papillon Lefevere syndrome, Down’s syndrome, Neutropenia, Chediak Higashi syndrome, Hypophosphatasia, Hyperparathyroidism, Acute leukemia, Paget’s disease etc.
7. Bone factor concept of Glickman: “When a generalized tendency toward bone resorption exists, bone loss initiated by local inflammatory processes may be magnified. This systemic influence on the response of alveolar bone has been termed the bone factor in periodontal disease. The bone factor concept, developed by Irving Glickman in early 1950s, envisioned a systemic component in all cases of periodontal disease. In addition to the amount and virulence of plaque bacteria, the nature of the systemic component, not its presence or absence, influences the severity of periodontal destruction.
Although the term “Bone factor” is not in current use, the concept of a role played by systemic defense mechanisms has been validated, particularly by studies of immune deficiencies in severely destructive types of periodontitis, such as juvenile forms of the diseases.

Factors affecting development of tooth mobility:
1. Magnitude, frequency and character of masticatory forces.
2. Amount of fiber bundles, in the periodontium and strength of alveolar bone.
3. Physical resistance of the periodontium.
4. Direction of the masticatory stress.
5. Physiological and systemic factors, which influence metabolic process of cells such as blood circulation in periodontium, age, nutrition and general health.
6. Para-functional habits and forces.

MICROSCOPIC FEATURES OF TOOTH MOBILITY –
The excessive forces produce molecular physico-chemical alteration of the ground substance and fibrous components of the tissues, atrophic, degenerative and necrotic changes. Increased compression and tension of the periodontal ligament are seen. With severe tension, widening, thrombosis, hemorrhage and tearing of the periodontal ligament and bone resorption are seen. There is temporary depression, in mitotic and the rate of proliferation and differentiation of fibroblasts, collagen and alveolar bone.
Grant et al (1995) found significant proportions of Campylobacter rectus and Peptostreptococcus microbes and elevated levels of Porphyromonas gingivalis in pockets of mobile teeth than that of non mobile ones.

Dynamics of tooth mobility
Tooth mobility seems to occur in two stages (Muhlemann 1967):
1) First, there is an initial or intra vascular stage where movement within the socket is associated with redistribution of the fluids, interstitial contents and fibers.
2) The second stage occurs gradually and includes elastic deformation of the alveolar bone proper in response to increased forces.

FORCES ON TEETH:
1. Normal or Physiologic forces:
Teeth and their supporting structures are subjected to severe occlusal forces of up to 50 mg during mastication. The presence of tissue fluids and arrangement of PDL fibers are such that these intermittent heavy forces can be properly accommodated without tissue destruction. These forces are transmitted through PDL fibers to the alveolar bone proper.

2. Orthodontic or Pathologic forces:
When unidirectional orthodontic force exceeding the adaptive capacity is applied to a tooth, pressure is exerted on side of the periodontal ligament in the direction of the force and tension on the opposite site. In undermining resorption, bone is resorbed towards the socket with eventual resorption of the socket wall, where as on tension side, new bone is opposed on the socket lining maintaining the constant width of the periodontal space.

3. Jiggling Pathologic Forces:
Forces applied to a tooth during function and parafunction may exceed the adaptive capacity. These jiggling forces may move a tooth in a faciolingual, mesiodistal, or vertical direction, along the X, Y or Z axis. As a result of pressure being exerted in all direction, the entire periodontal ligament behaves as it is subjected to pressure only. A force that exceeds the tooth’s adaptive capacity leads to the lesion of trauma from occlusion.

CORRELATION BETWEEN TOOTH MOBILITY AND OCCLUSION
Trauma From Occlusion
“When occlusal forces exceed the adaptive capacity of the periodontal tissue, injury results.” The resultant injury is termed trauma from occlusion.
So occlusal trauma is described as trauma to the periodontium from functional and para-functional forces causing damage to the attachment apparatus of the periodontium by exceeding its adaptive and reparative capacities.

– Generally, two forms of occlusal trauma are recognized:

1. Primary occlusal trauma
It is a condition in which the pathologic occlusal forces considered the principal etiology for occlusal changes in the periodontium.

2. Secondary occlusal trauma
It occurs when the periodontium is already compromised by inflammation and bone loss. Teeth with a reduced adaptive capacity and compromised periodontium may then migrate when subjected to certain occlusal forces. Factors such as frequency, duration and velocity of those occlusal forces, not just their magnitude, may be of greater significance in the development of tooth hypermobility. This mobility is a common clinical sign of occlusal trauma.

TOOTH MOBILITY INDICES
a. Miller’s Index (1938):
i) The first distinguishable sign of movement.
ii) The movement of the tooth which allows the crown to deviate within 1 mm       of its normal position.
iii) Easily noticeable and allows the tooth to move more than 1mm in any direction or to be rotated or depressed in the socket.

b. Modified Miller’s index:
Scorer of 0, 0.5, 1, 1.5, 2.5, 3 are utilized.

c. Prichard’s index (1972)
i) Slight mobility.
ii) Moderate mobility.
iii) Extensive movement in a lateral or mesiodistal direction combined with vertical displacement in the alveolus.
iv) Or sign can be used for added refinement.

d. Wasserman’s Index (1973)
i) Normal
ii) Slight mobility less than 1 mm of buccolingual movement.
iii) Moderate mobility – up to approximately 2 mm of buccolingual movement.
iv) Severe mobility – more than 2 mm of movement.

e. Nyman’s Index (1975)
Zero degree – Normal – less than 0.2 mm
Degree 1 – Horizontal / Mesiodistal mobility of 0.2 – 1mm
Degree 2 – Horizontal / Mesiodistal mobility of 1-2 mm.
Degree 3 – Horizontal / Mesiodistal mobility exceeding 2mm and / or vertical mobility.

f. Flezar’s Index (1980)
Mo – Firm Tooth
M1 – Slight increased mobility
M2 – Definite to considerable increase in mobility but not impairment of
function.
M3 – Extreme mobility, a loose tooth that would be incomparable in
function.

g. Glickman’s Index (1972)
i) Normal mobility
ii) Pathologic mobility
iii) Grade I – slightly more than normal
Grade II – moderately more than normal
Grade III – Severe mobility faciolingually and or / mesiodistally combined   with vertical displacement.

h. Lovdal’s Index (1959)
First degree – teeth that were somewhat more mobile than normal.
Second degree – teeth showing conspicuous mobility in transversal but not axial direction. Third degree – teeth being mobile in axial as well as on transversal direction.

Measurement of tooth mobility
Measurement of tooth mobility is important to evaluate the condition of periodontium in research oriented studies and for diagnosis and treatment planning.
There are numerous mobilometers, to name a few.
1. Elbrecht’s indicator (1939)
2. Werner’s Oscillator (1942)
3. Dreyfus vibrator (1947)
4. Zinrner’s oscillograph (1949)
5. Manly’s device (1951)
6. Muhlemann’s Macro-periodontometer and Micro-periodontometer, Pictons gauge (1957)
7. Parfitt’s transformer (1958)
8. Joel’s technique (1958)
9. Goldber’s device (1961)
10. Korber’s transducers, USAFSAM periodontometer (O’Leary and Rudd 1963)
11. Pameijer’s device (1973)
12. Laser method (Ryden 1974)
13. Persson and Svensons device (1980)
14. Periotest (Schulte 1987, Simons AG, Germany)

PERIODONTOMETER: (Muhlemann 1957)
By means of the “Periodontometer” a small force (100 pounds) is applied to the crown of a tooth. The crown starts to tip in the direction of the force. The resistance of the tooth supporting structures against displacement of the root is low in the initial phase of force application and the crown is moved only5/100 to 10/100mm.
PERIOTEST
The Periotest device dynamically measures the reaction of the periodontium to a defined percussive force applied to the tooth produced by a tapping device.
It is connected by table to a unit which controls functions and analyses measurements. A metal rod housed in the interior of the hand piece, the tapping head is accelerated to a present speed of 0.2 m/s (meters per second) and maintained at constant speed by compensation for the influence of friction and gravitation. Upon impact, the tooth is slightly deflected and the tapping head is decelerated.
The contact time between the tapping head and the tooth varies between 0.3 and 2 ms (milli seconds). The contact time is shorter for teeth whose alteration ability of the periodontium is greater and which are less mobile. The tapping head is electro magnetically retracted into the hand piece. In 4 seconds, 16 exact defined tapping impulses are applied to the tooth and 10,000 signals for deceleration are registered and analyzed by the measuring unit. Invalid measurements are recognized as such and eliminated.
Since the contact times are not clinically meaningful, the unit displays a value called the “Perio test value” (PTV). The value is calculated from the contact time between tapping head and tooth and ranges from – 8 to +50, corresponding to four different degrees of mobility.

Goodson (1988) confirmed the correlation between PTV and clinical mobility index (MI). He showed the periotest differentiates between 39 units for the mobility indices 0 to 3.
In a comparative study, stepwise multiple linear regression analysis at Periotest values compared with clinical parameters demonstrated that the influence of bone loss is far more important than other clinical parameters, indicating that the periotest value dependent to a large extent on bone loss. The greater the alveolar bone height, the lower the periotest value.
Of the other diagnostic valves tested, the pocket depth is correlated somewhat more strongly with periotest value than recession and the papillary hemorrhagic index. The correlation between the PTV and bone loss was stronger in the maxilla than in the mandible. Periodontally healthy teeth also had higher periotest value in the maxilla.
In tooth with non inflammatory recession and simultaneously TMJ dysfunction syndrome contribute to a significant increase in the periotest values for incisors. This is possibility due to increased alveolar destruction by bruxism.
In addition, the high sensitivity of the periotest method provides a means for early recognition of changes in the periodontium on a result of periodontal diseases.
Even though standardization of the grading of mobility would be helpful in diagnosing periodontal disease and in evaluating the outcome of treatment, these devices are not widely used.
As a general rule, mobility is graded clinically with a simple method such as the following:
The tooth is held firmly between the handless of two metallic, instruments or with one metallic instrument and one finger, and an effort is made to more it in all directions.
“It is not the length of the excursive movement of the crown that is important from a biologic point of view, but the displacement of the root within the remaining periodontal ligament”. Increased crown displacement (tooth mobility) may also be detected in a clinical measurement where a “Horizontal” force is applied to teeth with angular bony defects / or increased width of the periodontal ligament. If this mobility is not gradually increasing – from one observation interval to the next – the root is surrounded by a periodontal ligament of increased width but normal composition. This mobility should be considered “Physiologic” since the movement is a function of the height of the alveolar bone and the width of the periodontal ligament.
Only progressively increasing tooth mobility which may occur in conjunction with trauma from occlusion and which is characterized by active bone resorption and which indicates the presence of inflammatory alterations with in the periodontal ligament tissue, may be considered “Pathologic”.

TOOTH MOBILITY REVISTED:
1) (According to Charles Anderegg and David Metzler, J.P. July 2001)
Our commonly used parameter, degrees of millimeter movement, gives incomplete diagnostic and prognostic information. Current methods of grading or classifying mobility give no indication of the mobility is pathologic, physiologic or adaptive in nature.
2) So adding the designator (A) for adaptive and (P) for pathologic to the current grading or classification scheme would add the critical element for determining necessary additional occlusal or periodontal treatment.
3) Pathologic mobility, as defined, would include any degree of movement that may be reduced or eliminated once the pathologic factors is identified and corrected. Such etiologic factors would include inflammatory disease such as periodontitis, occlusal factors, parafunctional habits and iatrogenic factors.
4) Adaptive mobility, as defined, would include the absence of an etiologic factor that might be improved upon to directly improve stability by decreasing or eliminating tooth mobility. While pathologic mobility would certainly require treatment, adaptive mobility might or might not. Progressing mobility, whether adaptive or pathologic, would of course require treatment to stabilize the situation.
5) So we feel that adding the designator (A or P) to current descriptive terminology would, in a broad sense, address the etiology of existing mobility and complement current methods used to measure the degrees of mobility.

TREATMENT OF INCREASED TOOTH MOBILITY
A number of situations will be described here which may call for treatment aimed at reducing an increased tooth mobility.

Situation – I:
Increased mobility of a tooth with increased width of the periodontal ligament but normal height of the alveolar bone:
– If a tooth is fitted with an improper fitting a crown restoration, occlusal interferences develop and the surrounding periodontal tissues become the seat the inflammatory reactions, i.e. trauma from occlusion.
– If the restoration is so designed that the crown of the tooth in occlusion is subjected to undue forces directed in a buccal direction, because resorption phenomena develop in the buccal – marginal and lingual – apical pressure zones with a resulting increase of the width of the periodontal ligament in these zones.
– The tooth becomes hyper mobile or moves away from the “traumatizing” position. The resulting increased mobility of the tooth should be regarded as a physiologic adaptation of the periodontal tissues to the altered functional demands.
Fig. (a). contact relationship between a mandibular and a maxillary premolar in occlusion. Occlusion results in horizontally directed forces (arrows) which may produce an undue stress concentration within the “brown” areas of the periodontium of maxillary tooth. Resorption of alveolar bone and a widening of the periodontal ligament can be detected, leading to increased mobility. Following adjustment of the occlusal correction, the horizontal forces are reduced. This results in apposition “red areas” and normalization of the tooth mobility.

Situations – II:
Increased mobility of a tooth with increased width of the periodontal ligament and reduced height of the alveolar bone:
– If a tooth with a reduced periodontal tissue support is exposed to excessive horizontal forces, inflammatory reactions develop in the pressure zones of the periodontal ligament with accompany bone resorption. These alterations are similar to those which occur around a tooth with normal height of the supporting structures (as seen in situation 1). The alveolar bone is resorbed, the width of the PDL is increased in the pressured tension zones and tooth becomes hyper mobile.
– If the excessive forces are reduced or eliminated by occlusal adjustment bone apposition to the “pre trauma” level will occur, the periodontal ligament will regain its normal width and the tooth will become stabilized.

Conclusion
Situations I and II oculusal adjustment is an effective therapy against increased tooth mobility when such mobility is caused by an increased width of periodontal ligament.

Situation – III:
Increased mobility of a tooth with reduced height of the alveolar bone and normal width of the periodontal ligament:
– In this case tooth mobility can not be reduced or eliminated by occlusal adjustment. If such increased tooth mobility does not interfere with the patients chewing function or discomfort, no treatment is required.
– If the patient experiments the tooth mobility as disturbing, however the mobility can in this situations be reduced only by splinting, i.e. by joining the mobile tooth / teeth together with other teeth in jaw into a fixed splint for example “A – splint”. A-splint, according to Glossary of Periodontal terms (1986) is an appliance designed to stabilize mobile teeth”. A-splint can be fabricated in the form of joined composite filling, fixed bridges removable partial prosthesis etc.

Situations – IV:
Progressive (increasing) mobility of a tooth (teeth) as result of gradually increasing width of reduced periodontal ligament:
– Often in cases of advanced periodontal disease the tissue destruction may have reached a level where extraction of one or several teeth cannot be avoided. Teeth which in such a dentition are still available for periodontal treatment may, after therapy, exhibit such a high degree of mobility or even signs of progressively increasing mobility – that there is an obvious risk that the forces elicited during function may mechanically disrupt PDL components and cause extraction of the teeth. Only by means of a splint will it be possible to maintain such teeth.
– In such cases fixed splint has two objectives.
To stabilize hyper mobile teeth and
To replace missing teeth.
– Splinting is indicated when the periodontal support is so reduced that the mobility of the teeth is progressively increasing. i.e., when a tooth or a group of teeth during functions are exposed to extraction forces.

Situations – V:
Increased bridge mobility despite splinting:
– In patients with advanced periodontal disease it can often be observed that the destruction of the periodontium has progressed to varying levels around different teeth and tooth surfaces in the dentition. They may also be distributed in the jaw in such a way as to made it difficult, or impossible, to obtain a proper splinting effect even by means of a cross arch bridge The entire bridges splint may exhibit mobility in frontal and / or lateral directions. Neither progressive tooth mobility nor progressive bridge mobility can be accepted.
– In cases of extremely advance periodontal disease, a cross arch splint with an increased mobility may be regarded as an acceptable result of rehabilitation. It requires particular attending regarding the design of the occlusion.
– In cases of severity advanced periodontal disease it is often impossible to anticipate in the planning phase whether a bridge / splint after insertion will show signs of instability and increasing mobility. In such cases, a provisional splint should always be inserted.
– Any alteration of the mobility of the bridge / splint can be observed over a prolonged period of time and the occlusion continuously adjusted. Until, after 4-6 months, it is known whether stability can be achieved (i.e. no further increase of the mobility).
– Conclusion: An increased mobility of a cross arch bridge / splint can be accepted provided the mobility does not disturb chewing ability or comfort and then mobility of the splint is not progressively increasing. Splints can be temporary, permanent, extracoronal, intra coronal, removable, fixed or fiber or resin bonded etc.
– However through are 2 schools at thought regarding mobility and splinting. Waerhaug and co-workers feel that increase in mobility do not necessarily represent a state of pathology and does not require splinting. But Muhlemann strongly advocates that increase in mobility is pathological which requires treatment. However, a study of Kegel et al (1979) revealed no difference in mobility reduction between splinted and unsplinted teeth over 17 weeks period.

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